Hm.. I am not sure, but I think so. I am still using the Zoomed UTHs hooked to rheostats. I had to adjust them before putting in the snakes, and I found that turning them down a good 2/3 of what they were on the tanks, made the right temp in the racks. Maybe b/c of the non-gap between the rack surface and the tub.. w/ the tanks, I had a three-inch gap between tank floor and table.
I LOVE the space saving, and the neater-looking aspect of it too; no more odd-sized tanks everywhere.